Apparatus for the control of fuel injection for an internal combustion engine

ABSTRACT

Apparatus for the control of a fuel injection type internal combustion engine comprising a first negative pressure governor arranged to be operated by the negative pressure of the engine to control the amount of fuel injection of a fuel injection pump depending on the negative pressure force. A second negative pressure governor is arranged to operate the amount of fuel injection of the fuel injection pump to increase the amount of fuel injected according to increase in the engine speed after the throttle valve has been opened wide.

United States Patent 1191 Okura Aug. 7, 1973 [5 1 APPARATUS FOR THECONTROL OF FUEL 3,494,337 2/1970 Alderson 123/140 MP NJECTION FOR ANINTERNAL 3,077,873 2/1963 Parks et a1... 123/140 MP 3,435,813 4/1969Wagner 123/140 MP COMBUSTION ENGINE v 3,670,710 6/1972 Date 123/140 MP[75] Inventor; Takao ()kura, Oi-machi, Japan 2,562,656 7/1951 Blakeslee123/140 MP [73] Assignee: Honda Giken Kogyo Kabushiki Prim y x min r-Lar n M- Go dridge Kaisha, Tokyo, Japan M Assistant E2rqminer-ort Flint I[22] Filedz- Dec 29, 1971 Attorney-Eric H. Waters, John G. Schwartz eta1.

[21] Appl. No.: 213,267 I [57] ABSTRACT Apparatus for the control of afuel injection type inter- [30] Foreign Application Priority Data nalcombustion engine comprising a first negative pres- Dec. 31, 1970 Japan45/123276 Sure governor arranged be Operated y the negative pressure ofthe engine to control the amount of fuel in- 52 us. 01. 123/140 MP,123/140 MC, 123/139 Aw j of a fuel i P p depending on h 3 -511 1m. (:1.F02rl 11/08, F02d 1/06 We Pressure force- A Second negative Pressuregover- [58] Field 6: Search 123/140 MC, 140 MP, nor is arranged toOperate the amvum of fuel'injeclion 123,139 w of the fuel injectionpumpto increase the amount of fuel injected according to increase in theengine speed [5 R fer n Cited after the throttle valve has been openedwide.

UNITED STATES PATENTS 7 Claims, 1 Drawing Figure 2,569,664 10/1951Gewinner 123/140 MC APPARATUS FOR THE CONTROL OF FUEL INJECTION FOR ANINTERNAL COMBUSTION ENGINE BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to control apparatus in a fuelinjection type internal combustion engine wherein the amount of fuelinjection is controlled by negative pressure in a suction pipe.

2. Prior Art In a conventional fuel injection type internal combustionengine wherein the fuel injection is controlled by governing theoperation of a fuel injection pump-by a negative pressure governorutilizing a suction pipe negative pressure, it is characteristic that,whenthe engine is operated at high speed after the throttle valve isopened wide, the amount of fuel injection is reduced, despite anincreased suction efficiency, by apulsation effect or an inertia effectof the suction air. In fact, the negative pressure governor is operatedin a direction to decrease the amount of fuel injection becausethenegative pressure within the suction pipe is increased. Consequently,there is brought about the disadvantage that the air-fuel ratio at highspeed engine operation is too lean causing poor engine operation.

SUMMARY OF THE INVENTION An object of the invention is toprov idecontrol apparatus for a fuel injection type internal combustion engineby whichthe amount of fuel injection can be made dependent on enginespeed after the throttle has been opened wide.

In accordance with the invention, after the throttle valve has beenopened wide, the fuel injection pump is controlled by a second governoroperated in accordance with engine speed.

The second governor is connected to the suction inlet of the engine viaa passageway containing a valve which is opened when the throttle valveis opened wide. Thereupon, the second governor can override the actionof the first governor on the fuel injection pump so that the amount offuel delivered to the engine will be made responsive to engine speed.

BRIEF DESCRIPTION OF THE DRAWING The sole FIGURE of the drawing is alongitudinal sectional view through apparatus according to thisinvention.

DETAILED DESCRIPTION A control casing I is divided at one side intofirst and second negative pressure chambers 4, 5 by diaphragms 2. 3, andthe first negative pressure chamber 4 is in communication through aboost pipe 6 with the interior of a suction pipe 7 of an internalcombustion engine E. Hence, the interior of the first negative pressurechamber 4 is subjected to the negative pressure produced behind athrottle valve 8 in suction pipe 7.

A branch pipe 9 diverges from the middle portion of the boost pipe 6 andis in communication with the second negative pressure chamber 5. Thebranch pipe 9 is provided with a valve 10 for opening and closing thebranch pipe 9. A valve body 12 of valve 10 is positioned to be operatedby a cam 13, mounted on a shaft coaxial with and rigidly coupled to arotating shaft 8' integral with the throttle valve 8', so that the valve10 is opened at the timeof full opening of the throttle valve 8. Theinterior of the valve 10 is in communica tion with atmospheric airthrough a throttle 11.

A first governor spring 14 is mounted under stress within the firstnegative pressure chamber 4, so that this first governor spring 14serves to urge the diaphragm 2 to the right in the drawing against theaction of the suction negative pressure force which is produced withinthe first negative pressure chamber 4. A second governor spring 14 ismounted under stress within the second negative pressure chamber 15, so

.that this second governor spring 15 serves to urge the v diaphragm 3 tothe left in the drawing.

A shaft l6,rotated by the operation of the engine E, is supported by thecasing I, and a control cam 17 for operating a fuel injection pump P ismounted on the periphery of rotating shaft 16 so as to slidable in theaxial direction. The control cam 17 is coupled with a pin 19 passingthrough slits 18 in the rotating shaft 16, so that the cam 17 can berotated togetherwith the rotating shaft 16 within the range of thelength of vthe slits 18.

A sliding member 21 is coupled with the pin 19' and is mounted within ahollow portion 20 of the rotating shaft 16. The outer end of slidingmember 21' faces an end surface of a first actuator or governor shaft 22connected to the diaphragm 2 and it also faces an end portion of asecond actuator or governor shaft 23 connected to the diaphragm andmounted slidably on the first governorshaft 22. A spring 24 is mountedin the hollow portion 20 to urge the control cam 17 to the left, thatis, in a direction to decrease-the amount of fuel injected.

A plunger 25 of the fuel injection pump P is mounted in the controlcasing I so as to be movable up and down, and the lower end of plunger25 is in pressure contact with the cam surface of the control cam 17 bythe action of a return spring 26.

The inlet side of the fuel injection pump P is connected to a feed pump28 connected to afuel tank 27, and the outlet side of the fuel injectionpump 'P is connected to a fuel injection nozzle 29 projecting into thesuction pipe 7.

If the engine E is now operated and a negative pressure is generatedwithin the suction pipe 7, this negative pressure acts on the interiorof the first negative pressure chamber 4 through the boost pipe 6. Ifthe negative pressure force within the chamber 4 is increased, thediaphragm 2 is drawn thereby against the resilient force of the firstgovernor spring 14 and accordingly the first governor shaft 22 is movedto the left, so that the control cam 17 is moved to the left, that is,in the direction of decreasing fuel injection amount by the resilientforce of the spring 24. The stroke of the plunger 25 produced by therotation of the rotating shaft 16 becomes smaller and consequently theamount of fuel injection by the fuel pump P is decreased, and thus thedecrease in the amount of fuel injection is in proportion to thedecrease in the amount of suction air in the suction pipe 7. If thenegative pressure within the suction pipe 7 is decreased, the diaphragm2 is moved to the right by the action of the first governor spring 14,and the control cam 17 is moved to the right by the first governor shaft22, so that the stroke of the plunger 25 becomes larger and consequentlythe amount of fuel injection is increased. Thus an increase in theamount of fuel injection in proportion to an increase in the amount ofsuction air in the suction pipe 7 is obtained.

Since, during the foregoing operation, the valve 10 is kept closed untilthe throttle valve 8 is fully opened, the second negative pressurechamber 5 is not subjected to the negative pressure within the suctionpipe: 7.

When the engine is operated at high speed under full open condition ofthe throttle valve 8, the amount of suction air is increased but thenegative pressure within the suction pipe 7 is increased and the fuelinjection pump P is operated in the direction of decreasing fuelinjection, which brings about the tendency that the amount of fuelsupply does not satisfy the fuel requirement of the engine.

it is contemplated by this invention that, for overcoming such tendency,the amount of fuel injection after the throttle valve has been openedwide can be controlled in accordance with engine speed. Thus, when thethrottle valve 8 is fully opened, the cam 13 is rotated therewith andopens the valve whereby the interior of the second negative pressurechamber 5 is placed into communication with the interior of the suctionpipe 7.

Accordingly, under the full open condition of the throttle valve 8, thesuction negative pressure force which is increased with increase in theengine speed acts on the interior of the second negative pressurechamber 5 so as to move the diaphragm 3 to the right against theresilient force of the second governor spring 15, and thereby thecontrol cam 17 is moved, through the second governor shaft 23, to theright, that is, in the direction to increase the amount of fuelinjection.

Thus, the shortage of fuel upon increase in engine speed is obviated. Ifthe engine speed is lowered, the negative pressure within the negativepressure chamber 5 is decreased, so that the diaphragm 3 is moved to theleft, that is, in the direction to decrease the amount of tion isincreased even when the suction pressure is increased. Thisobviates thetendency to decrease the amount of fuel injection caused by increase ofthe suction negative pressure at the time of high speed engine operationwhen the throttle valve is wide open as in conventionalne'gativepressure governor type control apparatus-Thus, proper fuel injectionsatisfying the fuel requirement at the time of high speed operation canbe effected.

What is claimed is:

1. In a fuel injection type internal combustion engine having a fuelinjection pump with control means regulating the fuel delivery thereofto the engine in response to suction pressure in a first negativepressure chamber connected to a suction inlet leading to the engine andprovided with a throttle valve, an improvement comprising governor meanscoupled to the control means to operate the fuel pump to increase fueldelivery upon increase of engine speed when the throttle valve is wideopen, said governor means comprising a second negative pressure chambercoupled to said control means, a passageway connecting the secondnegative pressure chamber and the suction inlet, and valve means in saidpassageway for being opened when the throttle valve is wide open, andmeans connected to the valve means and the throttle valve to open saidvalve means when the throttle valve is wide open.

2. An improvement as claimed in claim 1 wherein said governor means iscoupled to the control means to override the effect of the suctionpressure in the first negative pressure chamber when the throttle valveis wide open. I

3. An improvement as claimed in claim 1 wherein said control meanscomprises a displaceable control member, a first actuator coupled to thefirst negative pressure chamber and facing said control member todisplace the same in accordance with the suction pressure in the firstnegative pressure chamber, and a second actuator facing said controlmember to displace the same in accordance with the suction pressure inthe second negative pressure chamber.

4; An improvement as claimed in claim 3 wherein the second actuator isslidable on the first actuator.

5. An improvement as claimed in claim 3 comprising displaceablediaphragms bounding each negative pressure chamber, the actuators beingconnected to respective diaphragms.

6. An improvement as claimed in claim 5 comprising a stressed spring ineach negative pressure chamber acting-on the respective diaphragms, thespring in the first chamber acting-on the associated diaphragm todisplace the first actuator and the control memberin a direction toincrease the amount of fuel delivery to the engine, the spring in thesecond chamber acting on the associated diaphragmto displace the secondactuator and th e control member in a direction to decrease the amountof fuel delivery to the engine.

7. An improvement as claimed in claim 3 wherein the actuators andsuction pressure chambers are'arranged so that application of suctionpressure in the first and second chambers tends to displace the controlmember in respectively opposite directions.

i t i i it

1. In a fuel injection type internal combustion engine having a fuelinjection pump with control means regulating the fuel delivery thereofto the engine in response to suction pressure in a first negativepressure chamber connected to a suction inlet leading to the engine andprovided with a throttle valve, an improvement comprising governor meanscoupled to the control means to operate the fuel pump to increase fueldelivery upon increase of engine speed when the throttle valve is wideopen, said governor means comprising a second negative pressure chambercoupled to said control means, a passageway connecting the secondnegative pressure chamber and the suction inlet, and valve means in saidpassageway for being opened when the throttle valve is wide open, andmeans connected to the valve means and the throttle valve to open saidvalve means when the throttle valve is wide open.
 2. An improvement asclaimed in claim 1 wherein said governor means is coupled to the controlmeans to override the effect of the suction pressure in the firstnegative pressure chamber when the throttle valve is wide open.
 3. Animprovement as claimed in claim 1 wherein said control means comprises adisplaceable control member, a first actuator coupled to the firstnegative pressure chamber and facing said control member to displace thesame in accordance with the suction pressure in the first negativepressure chamber, and a second actuator facing said control member todisplace the same in accoRdance with the suction pressure in the secondnegative pressure chamber.
 4. An improvement as claimed in claim 3wherein the second actuator is slidable on the first actuator.
 5. Animprovement as claimed in claim 3 comprising displaceable diaphragmsbounding each negative pressure chamber, the actuators being connectedto respective diaphragms.
 6. An improvement as claimed in claim 5comprising a stressed spring in each negative pressure chamber acting onthe respective diaphragms, the spring in the first chamber acting on theassociated diaphragm to displace the first actuator and the controlmember in a direction to increase the amount of fuel delivery to theengine, the spring in the second chamber acting on the associateddiaphragm to displace the second actuator and the control member in adirection to decrease the amount of fuel delivery to the engine.
 7. Animprovement as claimed in claim 3 wherein the actuators and suctionpressure chambers are arranged so that application of suction pressurein the first and second chambers tends to displace the control member inrespectively opposite directions.